Recent years have seen an explosion of interest in gourmet coffee products and the interest has not been limited to the purchase of coffee-based beverages from vendors who prepare the beverage on premise and purvey it to consumers over the counter. Similarly, the interest has not been limited to gourmet blends, coffee that may be purchased already ground, and then brewed in the home. Many consumers desire the ultimate in freshness and flavor and have taken to roasting their own beans and then grinding them shortly before the coffee brewing process is initiated.
As a consequence, there is an increasing market for coffee roasting apparatus that may be used in the home. A variety of coffee roasting apparatus have been devised to meet this market. Examples of such a coffee roasting apparatus are illustrated in U.S. Pat. No. 5,564,331 issued Oct. 15, 1996 to Song, and in application Ser. No. 09/134,324, filed Aug. 14, 1998, titled "APPARATUS FOR ROASTING COFFEE BEANS", to Kelley, the entire disclosures of which are herein incorporated by reference. These roasters work well for their intended purpose, but there is always room for further improvement.
For example, to achieve optimum roasting, it is necessary that the beans be uniformly heated. If the heating is not uniform, some of the beans may pop early in the roasting process and others, not at all. Consequently, uniform flavor cannot be obtained. Thus, there is a continuing need to improve the uniformity of heating, and/or provide uniformity of heating in connection with other improvements.
Similarly, it is desirable for the roasting temperature to be accurately controlled to assure maximum husk removal, as well as proper flavor development, which cannot occur if the roasting temperature is either too low or too high. The roasting temperature can be affected in a number of ways. For example, coffee roasters intended for home use have generally subjected the coffee beans to an air stream that is heated by an electrical resistance heater, the heat generation of which can be significantly affected by variation in line voltage.
To control the electrical resistance heater, and/or accommodate the voltage fluctuations, at least one coffee roaster has energized and de-energized the electrical resistance heater by opening and closing a relay. However, this may reduce the life of the relay and may provide fluctuations in the roasting temperature that are less than optimum.
Another common concern for home use coffee makers is the consistency from one roasting cycle to the next roasting cycle, which may occur several days apart. Typically, coffee roasters are provided with a mechanical timer that must be turned to the desired roasting time each time the roaster is used. It can be difficult to return the mechanical timer to precisely the same setting from one operation to the next to achieve the desired roast. Further, because of the time period between operation of the coffee roaster, a user may forget which setting on the timer has provided the user with the user's desired roast.
Another common challenge for all coffee roasters is the relatively high temperatures required for roasting the coffee beans. These temperatures create a number of concerns, including the safety of the user and the type of materials that can be used in the roaster to accommodate the high temperatures and the costs associated with such materials.
A concern somewhat related to the high temperature of the roasters is the energy efficiency of such roasters, which can require relatively large amounts of power to provide the high temperatures.
Other concerns include the potential for contaminants to enter the hot air stream of the coffee roaster, cooling of the coffee roaster components, the convenience of using the coffee roaster, and the appearance and functionality of the coffee roaster components.
The present invention is directed to addressing one or more of the above concerns.